code: def _get_X_train_2(self):
      X_train_a = gs.array([[EULER, 0], [0, 1]])[None, ...]
      X_train_b = gs.array([[EULER**4, 0], [0, 1]])[None, ...]
      return gs.concatenate([X_train_a, X_train_b])
  
file_path: geomstats/tests/tests_geomstats/test_learning/data/mdm.py
imports: import geomstats.backend
  from geomstats.test.data import TestData
label_desc: Use image node_id 2 for calling the RiemannianMinimumDistanceToMeanSPDTestData obj's underlying member method code with example usage: obj._get_X_train_2() and returns: gs